Highland GuanPenelopina nigra

Sounds and Vocal Behavior

Vocalizations

For the following account on Highland Guan vocalizations, recordings were analyzed using software Raven Pro. Notes were marked in sonograms with the curser and following data were measured: peak frequency (frequency with the highest power), delta time, and center time. All means are given with standard deviation.

Male whistle: The most obvious sounds of Highland Guan are produced by the male. Mainly during the first part of the breeding season (January-April), males utter single, loud and far-carrying whistles which can be heard over more than a kilometer. This call is usually given while perched in the upper forest canopy, midstory, or sometimes on ground (Pullen 1983, González-García et al. 2001; K. Eisermann, personal observations), but it has also been reported during flight (Rowley 1984). A male’s whistle often provokes other males to vocalize (K. Eisermann, personal observations). Often the whistle precedes a wing-rattling which is produced during glides between perches. The whistle has been described as “long whistle, steady in volume but rising in pitch” (Land 1970). Based on recordings and sonograms of 5 individuals in the Guatemalan highlands, whistles ranged in length 2.3-3.1 s (mean: 2.6 ± 0.3, n = 6 calls of 5 individuals; K. Eisermann, personal observations). Peak frequency ranged 2062-2906 Hz (mean: 2469 ± 278, n = 6 calls of 5 individuals; K. Eisermann, personal observations). Sonogram 1 shows a typical whistle. The function of the whistle and combined wing-rattling is thought to be a territorial advertisement and a signal for sexual selection (Pullen 1983, del Hoyo and Motis 2004). Seasons of call activity may change between years. At Montaña Caquipec, Alta Verapaz, Guatemala, there was no call activity from September 1997 to February 1998, but in 1998 guans were calling until October (Eisermann 1999).

Juvenile calls: About two weeks old chicks gave series of soft short whistles wi-wi-wi, while an adult female and an adult male were uttering warning calls (K. Eisermann, personal observations, 13 June 2011).

Nonvocal Sounds

In the first part of the breeding season, males produce a sound during glides between perches, which has been pictorially described by several authors: “habit of ‘drumming’ ... emitted a sort of crushing or rushing noise, like that produced by a falling tree” (Salvin and Godman 1897-1904), “curious, whirring rattle ... sounds very much like a policeman’s rattle” (Dickey and van Rossem 1938), “loud crack, followed by a cascade of descending notes” (Land 1970), “ripping or drumming sound ... similar to the sound of a piece of cloth being forcefully torn” (Pullen 1983), “bizarre ‘crashing tree’ sound ... initially 1-2 raps, then a creaking, falling, rattling crash, ke’k’a,arrrrrrr” (Howell and Webb 1995).

The sound characters of the wing-drumming of five males in the Guatemalan highlands were as follows (K. Eisermann, personal observations). Each wing-drumming consisted of two types of introductory cracks, followed by a rattling (Sonogram 3).

The first kind of crack was a series of 1-4 notes, ranging in length 0.025-0.04 s (mean 0.035 ± 0.008 s, n = 11 notes of 5 individuals). Peak frequency of these notes ranged 422-985 Hz (mean 482 ± 170 Hz, n = 11 notes of 5 individuals). The interval between the center time of each crack ranged 0.10-0.27 s (mean 0.18 ± 0.05 s , n = 4 series of notes of 4 individuals). The interval between the center time of the last note of these cracks and the center time of the first note of the second kind of cracks was 0.3 s.

The wing-drumming was thought to be of vocal nature, produced by “rapid expulsion of air from the throat (Rowley 1984), until Pullen (1983) observed the feather vibration during the rattling. The introductory notes are assumed to be generated by wing-flaps during take-off from the perch. An obvious wing-flap noise is produced during wing beats after take off and before landing (sonogram 4).